The effects of amiloride, a Na+-H+ exchange inhibitor, on iliac artery stenosis after balloon injury in rabbits.

This study was designed to explore the effects of amiloride, a Na+-H+ exchange (NHE) inhibitor, on vessel stenosis by observing the expression of NHE-1 protein in vascular smooth muscle (VSM) after balloon injury and the effects of amiloride on VSM cell proliferation, migration, and excretion of extracellular matrices (ECMs). A total of 32 adult male New Zealand white rabbits were randomly divided into a balloon injury group (BG), an amiloride-treated group (AG), and a sham-operated group (SG). The left iliac artery was injured by inflating a 2.5 mm x 20 mm Foley catheter in BG and AG rabbits; in SG rabbits, the Foley catheter was inserted but not inflated. Amiloride (5 mg x kg(-1) x d(-1)) was injected intraperitoneally in AG and the same volume of distilled water was used in BG 3 days before balloon injury and for 28 days after the injury. The left iliac artery was stained by hematoxylin-eosin, alpha-actin, and Masson's trichrome to observe the vessel cava, neointima, media layer, and ECMs. NHE-1 proteins of the VSM were detected by Western blotting. A narrowing of the arterial cava, neointima formation, and thickened VSM layer were observed 28 days after balloon injury in BG and AG. However, in AG, the vessel cava was not as narrowed as that of BG and the intimal areas were to a lesser extent than in BG. In AG, the alpha-actin-positive areas and the ECM areas in the neointima were increased compared with SG, but to a lesser extent than in BG. The expression of NHE-1 protein in VSM was increased in BG and AG after balloon injury; however, the levels in AG were significantly less than in BG. In conclusion, VSM cell proliferation, migration, and excretion of ECMs contributed to vessel stenosis in the BG and AG rabbits. The expression of NHE-1 protein in VSM increased after balloon injury. Amiloride, an inhibitor of NHE-1, can limit the development of vessel stenosis through inhibition of VSM cell proliferation, migration, and excretion of ECMs.

Dehydroepiandrosterone reverses systemic vascular remodeling through the inhibition of the Akt/GSK3-{beta}/NFAT axis.

BACKGROUND: The remodeled vessel wall in many vascular diseases such as restenosis after injury is characterized by proliferative and apoptosis-resistant vascular smooth muscle cells. There is evidence that proproliferative and antiapoptotic states are characterized by a metabolic (glycolytic phenotype and hyperpolarized mitochondria) and electric (downregulation and inhibition of plasmalemmal K(+) channels) remodeling that involves activation of the Akt pathway. Dehydroepiandrosterone (DHEA) is a naturally occurring and clinically used steroid known to inhibit the Akt axis in cancer. We hypothesized that DHEA will prevent and reverse the remodeling that follows vascular injury. METHODS AND RESULTS: We used cultured human carotid vascular smooth muscle cell and saphenous vein grafts in tissue culture, stimulated by platelet-derived growth factor to induce proliferation in vitro and the rat carotid injury model in vivo. DHEA decreased proliferation and increased vascular smooth muscle cell apoptosis in vitro and in vivo, reducing vascular remodeling while sparing healthy tissues after oral intake. Using pharmacological (agonists and antagonists of Akt and its downstream target glycogen-synthase-kinase-3beta [GSK-3beta]) and molecular (forced expression of constitutively active Akt1) approaches, we showed that the effects of DHEA were mediated by inhibition of Akt and subsequent activation of GSK-3beta, leading to mitochondrial depolarization, increased reactive oxygen species, activation of redox-sensitive plasmalemmal voltage-gated K(+) channels, and decreased [Ca(2+)](i). These functional changes were accompanied by sustained molecular effects toward the same direction; by decreasing [Ca(2+)](i) and inhibiting GSK-3beta, DHEA inhibited the nuclear factor of activated T cells transcription factor, thus increasing expression of Kv channels (Kv1.5) and contributing to sustained mitochondrial depolarization. These results were independent of any steroid-related effects because they were not altered by androgen and estrogen inhibitors but involved a membrane G protein-coupled receptor. CONCLUSIONS: We suggest that the orally available DHEA might be an attractive candidate for the treatment of systemic vascular remodeling, including restenosis, and we propose a novel mechanism of action for this important hormone and drug.

Mixed arterio-venous insufficiency in random skin flaps in the rat: is the application of medicinal leeches beneficial?

BACKGROUND: Leeches are commonly used in reconstructive surgery for the treatment of venous congestion in flaps. Documented mechanisms of action are (1) injection of the anticoagulant hirudin; (2) active suction of blood; and (3) passive oozing of the bite wound. Even though the benefits of leeches in venous congestion are widely accepted, little is known about their effects in mixed arterio-venous insufficiency. METHODS: Thirty Wistar rats were randomized into three groups (n = 10 each), and 9 x 3 cm ischemic random skin flaps were elevated on the rat dorsum. Group 1 served as controls. In group 2, one leech was applied to the distal part of the flap and in group 3, three leeches were applied, one at a time, at 8 h intervals. Postoperatively, flap survival and perfusion were quantitated by daily planimetry and laser-Doppler imaging. RESULTS: The application of a single leech on postoperative day 7 did not lead to any statistically significant changes in total flap survival or tissue perfusion. Triple leech application, however, caused a significant decrease in flap survival of 6.6% at day 7 (3x leech versus control: 45.8% +/- 8.5% versus 52.4% +/- 8.5%, respectively) (P < 0.01) and a decline in flap perfusion of 13% (3x leech versus control: 71.3% +/- 16.6% versus 84.3% +/- 9.3%, respectively) (P < 0.01). CONCLUSION: The data demonstrate that the application of leeches in the setting of mixed arterio-venous insufficiency can be hazardous to flap viability. Pure venous congestion with an adequate arterial supply remains the only indication for controlled leech application in the clinical setting.

Omega-3 polyunsaturated fatty acid in peripheral arterial disease: effect on lipid pattern, disease severity, inflammation profile, and endothelial function.

BACKGROUND & AIMS: Peripheral arterial disease (PAD) is strongly associated with endothelial dysfunction and inflammation, which portend a high cardiovascular risk. Accordingly, we investigated the effects of omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation on endothelial function and inflammatory status in affected individuals. METHODS: PAD patients were randomly divided into two groups. In Group I (n=16) pre-enrollment therapy was not modified, while in Group II (n=16) n-3 PUFAs 1 g b.i.d. for 3 months were added to the previous treatment. Endothelial function was assessed by measuring plasma soluble thrombomodulin (sTM) and brachial artery flow-mediated dilation (FMD), and the inflammatory status by measuring high-sensitivity C-reactive protein and myeloperoxidase. RESULTS: In Group II, n-3 PUFAs reduced sTM levels from the median value of 33.0 ng/mL (interquartile range 16.7, 37.2) to 17.0 ng/mL (11.2, 33.7) (p=0.04), and improved FMD from 6.7% (3.7, 8.7) to 10.0% (6.2, 14.2) (p=0.02). Conversely, these markers did not change in Group I. After 3 months, the levels of inflammatory markers remained unmodified in both groups. CONCLUSIONS: In PAD, n-3 PUFAs induced a marked improvement in endothelial function. Conversely, they did not affect the inflammatory status. In future, large, prospective studies are needed to investigate whether n-3 PUFAs, by improving endothelial function, would reduce the incidence of ischemic events in a population at high risk.

Dietary supplementation with fish oil modifies the ability of human monocytes to induce an inflammatory response.

Monocytes/macrophages are key orchestrators of inflammation and are involved in the pathogenesis of chronic inflammatory disorders, including atherosclerosis. (n-3) Fatty acids, found in fish oil, have been shown to have protective effects in such disorders. To investigate possible modes of action, we used a monocyte:endothelial cell (EC) coculture model to investigate the pro-inflammatory potential of monocytes. Monocytes were isolated from the blood of donors with peripheral arterial disease (PAD) or control donors, before and after a 12-wk supplementation of their diet with fish oil. The monocytes were cultured with human umbilical vein EC (HUVEC) for 24 h, after which the ability of the HUVEC to recruit flowing neutrophils was tested. Monocytes from either group of donors stimulated the EC to support the adhesion and migration of neutrophils. Fish oil supplementation reduced the potency of monocytes from normal subjects, but not those from patients with PAD, to induce recruitment. Concurrent medication may have acted as a complicating factor. On subgroup analysis, only those free of medication showed a significant effect of fish oil. Responses before or after supplementation were not closely linked to patterns of secretion of cytokines by cultured monocytes, tested in parallel monocultures. These results suggest that fish oil can modulate the ability of monocytes to stimulate EC and that this might contribute to their protective effects against chronic inflammatory disorders. Benefits, however, may depend on existing medical status and on other treatments being received.

Clinical, cellular, and molecular aspects of arterial calcification.

Arterial calcification is a complex and independently regulated process with risk factors similar to those for atherosclerotic occlusive disease. It may develop either within the atherosclerotic intima or in the media. When calcification is found in coronary or lower extremity arteries, it is an independent predictor of cardiovascular events and lower extremity amputation. Recent evidence suggests a role for several endogenous stimulators and inhibitors in the pathogenesis of arterial calcification. Inflammatory mediators and matrix-degrading enzymes are also thought to control the progression of calcification in humans. Current research involves efforts to define the complex interactions between cellular and molecular mediators of arterial calcification.

Hyperbaric oxygen and bone marrow-derived endothelial progenitor cells in diabetic wound healing.

Endothelial progenitor cells (EPCs) are the key cellular effectors of postnatal vasculogenesis and play a central role in wound healing. In diabetes, there is a significant impairment in the number and function of circulating and wound-tissue EPC. Recent evidence indicates, that tissue-level hyperoxia achieved by therapeutic hyperbaric oxygen protocols (HBO2) can increase the mobilization of EPC from the bone marrow into peripheral blood. In this paper we review the recent reports on hyperoxia-mediated mobilization of bone marrow-derived EPC and postulate avenues of future research in this area as it applies to improving healing in chronic wounds affected by diabetes and peripheral arterial disease (PAD).

The management of lower extremity wounds complicated by acute arterial insufficiency and ischemia.

Although wound care therapy has made significant advances in the past several years, clinicians encounter dilemmas on a day-to-day basis. One of these dilemmas is managing ischemic wounds. Certain characteristics (ischemic appearance, a history of a lack of healing, physical examination that finds no pulses, or a transcutaneous oxygen evaluation to suggest tissue hypoxia) will identify the wound as hypoxic or related to arterial disease. The clinician faces several decisions: Should an arteriogram be performed? Should an MRI or ABIs be ordered? Is a vascular surgery consult necessary? In response to this area of diagnostic and management conflict, the authors developed an algorithm for the treatment of patients with ischemic wounds. This article addresses the management of wounds primarily caused by peripheral arterial occlusive disease and includes discussion of the initial wound care consult, the factors that identify and classify patients with arterial wounds, and a description of how transcutaneous oximetry is used to evaluate this subgroup of patients. In addition, the concept of the Vascular Center is introduced and explained, including arterial vascular consultation and evaluation, arterial vascular anatomy, and noninvasive vascular studies that are important tools in the Vascular Center, as well as endovascular interventions such as arteriography, angioplasty and arterial stenting. The basics of arterial revascularization, the use of hyperbaric oxygen therapy to manage the patients with ischemic wounds, and outcome data from a case study illustrating the management algorithm utilized at the authors' facility also are presented.

[The influence of ozone therapy on endothelial damage markers in patients with atherosclerosis of lower extremities]. / Wplyw ozonoterapii na wskazniki uszkodzenia sródblonka naczyniowego u chorych na miazdzyce zarostowa.

The aim of study was to evaluate the influence of the treatment with oxygen-ozone mixture on the blood plasma antigen concentration of tissue plasminogen activator (t-PA) and von Willebrand factor (vWF) in patients suffering from atherosclerotic disease of lower extremities. The study was performed in the group of 28 (M/F 22/6) patients means aged 64.1 years with atherosclerotic diseases of lower extremities, in whom 2 weeks therapy with oxygen-ozone mixture was used. The control group consisted of 30 healthy volunteers in mean age 51.0 years. In the blood plasma obtained from the patients before and after treatment with oxygen-ozone mixture and from the control group determinations of t-PA and vWF antigen using ELISA were done. Both parameters were significantly increased in the patients before the treatment in comparison to the healthy controls. The treatment with oxygen-ozone therapy caused in patients slight statistically not significant raise of t-PA and vWF antigen showing the endothelial stimulation but not the destruction of vascular endothelium.